Tujerodne vrste so danes eden glavnih dejavnikov, ki prispevajo k upadanju globalne biodiverzitete. Z vnosi tujerodnih vrst prihaja do izumiranja domorodnih vrst, vplivi pa se odražajo tako na genetskem, individualnem kot populacijskem nivoju, pri čemer lahko prihaja do sprememb združb in celo ekosistemov. Čeprav so se vnosi tujerodnih vrst v naravne ekosisteme začeli že pred približno 10.000 leti s širjenjem človeške vrste po planetu, pa število vnosov novih vrst v zadnjih 100 letih eksponencialno narašča. V prispevku so prikazane ekološke osnove invazijskega procesa tujerodne vrste v novem okolju, ki gre navadno prek več invazijskih stopenj (Lockwood s sod. 2007): vnos, vzpostavitev populacije, širjenje in vpliv na domorodne vrste ter ekosisteme. Zbrani so tudi najbolj raziskani in objavljeni primeri tujerodnih vrst v Sloveniji, ki kažejo na to, da je problem tujerodnih vrst več kot očiten tudi pri nas.

Alien or non-native species are considered as one of the most important factors influencing global biodiversity lost. Consequences of alien species introductions were frequently extinctions of native species and impacts of alien species are expressed at genetic, individual and population level leading into changes of natural communities and ecosystems. Although first introductions had taken place already 10,000 years ago with the start of human population expansion on the planet, the introduction rate of alien species in natural ecosystems has exponentially increased in the last 100 years. In the article, the fundamental ecological principles of invasion process are given, which consists of several invasion stages (Lockwood et al. 2007): introduction, establishment, spread and impact on native species and ecosystems. The most searched and published examples of alien species in Slovenia are used as examples, which indicate the magnitude of the problem also in Slovenia.